A Unified Entry into the Ingenane, Tigliane, and Taxane Ring Systems

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…737 The diene part can also be tethered to the cycloheptatriene ring to give tricyclic products. 716 The reaction has been applied in natural product syntheses, 738 e.g., as entry into the ingenane, tigliane, and taxane ring systems, 739 and has been extended to (N-carboalkoxyazepine)Cr(CO) 3 and (η 6 -thiepine 1,1-dioxide)Cr(CO) 3 . 714 Stereochemical, regiochemical, and mechanistic aspects have been discussed, and it has been shown that the reaction can also be effected thermally in various ether solvents, giving cycloadducts identical to those produced in the photochemical reaction.…”

Metal-Mediated Cycloaddition Reactions of the η5-Cyclohexadienyl Ligand. Synthesis and Reactions of [5 + 2] Single and [5 + 2],homo[5 + 2] Double Cyclohexadienyl−Alkyne Adducts of Manganese

“…Transition metal-mediated cycloaddition reactions continue to attract interest because they allow the efficient and stereoselective synthesis of a variety of ring systems . In particular, medium-size carbo- and heterocyclic rings can be accessed via transition metal-mediated higher-order cycloadditions, , and Rigby and co-workers have shown that the [6 + 2] and [6 + 4] processes, originally discovered in the 1970s, , can be extended to a range of trienophiles − as well as to the syntheses of natural products. , We 16,17 and others 18 have reported the [6 + 2] addition of alkynes to the [(η 6 -triene)Cr(CO) 3 ] manifold (Scheme ), and more recently we and Kreiter and co-workers have extended this protocol to η 5 -dienyl ligands using tricarbonyl(η 5 -cyclohexadienyl)manganese(I). In these latter studies, sequential [5 + 2], homo [5 + 2] double alkyne additions to the dienyl ligand gave tricyclo[5.2.1.0 4,9 ]deca-2,5-dien-10-yl derivatives, further studies on which are described herein.…”

Synthesis, molecular and crystal structure of a tricarbonylchromium complex of 7-(2-phenyl-o-carboran-1-yl)cyclohepta-1,3,5-triene

“…2,3 Tricarbonylchromium complexes of substituted cycloheptatrienes can also be involved in the reaction. 4,5 The complexes can be prepared by reactions of a tropylium tricarbonylchromium complex with the corresponding nucleophiles. 6 Their tricarbonylchromium complexes can also enter the reactions, and the cycloaddition products obtained differ in structure from those prepared from the uncomplexed starting cyclohepta-1,3,5-triene derivatives.…”